Abstract: A system for supplying at least one lubrication point of a machine with lubricating oil includes: a lubricating oil reservoir; a delivery pump; a heat exchanger; a lubrication point; a plurality of lines including a lubricating oil supply line and a lubricating oil return line, the lubrication point being hydraulically connected to the lubricating oil reservoir via the lubricating oil supply line and the lubricating oil return line, a lubricating oil circuit being configured such that the lubricating oil flows through the lubricating oil circuit in one flow direction, the lubricating oil return line including an inlet point which is configured for a protective medium, which is air, being introduced into the lubricating oil return line.